The JM press, popularized by JM Blakely, has many variations used by powerlifters worldwide. This one is a great way to build triceps size and strength that will carry over to a big bench press.
Lifters new to the JM press often have difficulty figuring out where to stop the range of motion. Some perform these presses very shallow while others lower the bar until the forearm contacts the biceps. The floor variation makes it very easy to gauge depth – simply bring your elbows down until your triceps touch the floor, pause for one-second and explode up.